Some people are just begging for attention. Marketers are constantly trying to find ways to build brand awareness, often with clothing -- it's a common practice to make shirts and hats featuring ­company logos and slogans. To really grab your attention, some companies are using fabric displays -- techniques and systems designed to make dynamic images and text on clothes and other things made of fabric.

There are many different kinds of fabric displays. Some use a still image as a starting point, relying on fabric with special properties to make the design more eye-catching. Other fabric displays can show full video with sound. Each method relies on different technologies, and all have their advantages and disadvantages.

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A few fabric display techniques are readily available to the consumer market. Creative individuals have used fabric display technology to build elaborate costumes. Jay Maynard used electroluminescent wire (EL wire) in the costume he built based on the Disney film "Tron" -- his Web page describes how made the costume. His efforts gained national attention, and before long Maynard was making the talk show circuit as "the Tron guy."

In this article, we'll look at the different ways inventors have modified clothing to make a bigger impact on audiences. We'll learn about an idea for fur displays that use electrostatic charges to shocking effect. We'll see how a heat-sensitive dye can turn a normal T-shirt into a very large mood ring. After that, we'll explore the world of electroluminescent clothing. Then we'll see how LED and PLED displays can turn a normal outfit into an eye-catching light display. Finally, we'll learn about companies that have created clothing with built-in television and PC displays.

In the next section, we'll look at a way some engineers plan to use fur to create a dynamic fabric display.

Fur Fabric Displays

There has been some confusion about what, exactly, a fur fabric display is. Philips Electronics filed a patent application with the simple title "Fabric Display," though some science blogs and magazines have referred to it as "furry television." At its most basic level, this fur fabric display relies on a very simple technology. Patches of fur cover an image, and when the fur moves, it reveals the image underneath. It's a simple way to conceal and reveal designs.

The fabric display has three layers. The bottom layer is conductive, which means it can carry electricity from a power source -- like a small battery pack -- to the rest of the fabric to create an electrostatic field across the fur, which gives each strand of fur the same electrical charge.

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The next layer in a fur fabric display is the fabric's base color or design. This could be a company logo, a picture or just a particular color. The furry display doesn't change the design on the cloth; it just hides or reveals portions of the design at a given time.

The third layer is the fur. It can be any color, but it must be short enough so that when the user turns on the electrostatic field, the strands stand on end and reveal the design or color of the fabric underneath. For example, in a simple fur fabric display, you could use red fur to cover a blue shirt. When you turn on the power for the conductive layer, the red fur would stand on end, revealing the blue shirt underneath. To a distant observer, it would appear that the shirt had just magically changed colors.

The patent application refers to each small, visible section of the base fabric as a "pixel," which may be why some articles refer to the display as furry television. While it might be possible to approximate primitive animation techniques by printing one image across the fur layer and a slightly adjusted image on the fabric underneath, it's not quite the same as watching television on someone's jacket.

In the next section, we'll learn how some designers use a different form of energy to create fabric displays: heat.

Fur Fabric Functionality

To understand static electricity, we need to start all the way down at the atomic level. All matter is made up of atoms, which contain charged particles. Atoms have a nucleus consisting of neutrons and protons and a surrounding shell that is made up of electrons. Neutrons carry no charge, but protons have a positive charge and electrons have a negative charge. So, if an atom has more protons than electrons, its charge is positive, and if it has more electrons than protons, its charge is negative. Similar charges repel each other and opposite charges attract one another. An electrostatic field applied to fur creates a similar charge across the fur and the base of the material. Since similar charges repel one another, the fur moves as far away from the base of the material and other strands of fur as it possibly can, causing the strands to stand on end.

Thermochromic Fabric Displays

The word "thermochromic" looks a little intimidating at first, but the concept itself is pretty simple. Thermo comes from the Greek word "thermos," which means warm or hot. Chromic comes from "chroma," meaning color. A thermochromic substance changes color as it changes temperature. In fabrics, a special dye acts as the thermochromic agent.

Some thermochromic dyes change from colorful to clear, revealing the color of the fabric underneath. Companies can use thermochromic dyes in shirts that slowly reveal a company slogan or logo as the shirt heats up. When the shirt cools down, the logo seems to disappear.

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There are two widely used elements in thermochromic dyes, and both rely on chemical reactions:

Liquid crystals: These thermochromic dyes rely on liquid crystals contained in tiny capsules. The liquid crystals are cholestric, also known as chiral nematics, which means that its molecules arrange themselves in a very specific helical structure. These structures reflect certain wavelengths of light. As the liquid crystals heat up, the orientation of the helices changes, which causes the helices to reflect a different wavelength of light. To our eyes, the result is a change in color. As the crystals cool down, they reorient themselves into their initial arrangements and the original color returns.

Micro-encapsulate thermochromic system: In this system, the thermochromic dye contains millions of tiny capsules that look a little like an organic cell. Each capsule has an outer membrane and contains an organic, hydrophobic solvent, which makes it less likely that water will dilute or wash out the chemicals in the dye. The solvent contains particles of a color developer and a dye precursor. As the capsule heats up, the solvent melts and a chemical reaction causes the color developer to donate a proton to the dye precursor. In turn, this causes the precursor to develop into the dye itself and change color. When the dye cools down, the developer and precursor separate, the solvent resolidifies and the color returns to its original state.

Like fur fabric displays, thermochromic fabrics aren't animated -- they can only conceal and reveal designs or colors based on environmental conditions. While that might be enough for some people, others want even more dynamic clothing.

In the next section, we'll look at a technology that turns normal clothes into wearable neon signs -- electroluminescent fabric displays.

Blast from the Past

In the late 1980s, a company called Generra introduced a line of clothing that used thermochromic dyes. The company called the line Hypercolor. Schools across the United States were filled with students wearing the popular shirts and hats, most of them bearing a collection of handprints where other kids left their temporary marks.

The core layer is a copper wire that acts as a conductor in the EL wire's alternating current (AC) power system.

On top of the copper is a coating of electroluminescent phosphor. This is the material that will emit light after encountering an AC electric field.

The next layer consists of two wires wrapped around the phosphor. These wires complete the second half of a circuit, the first half consisting of the copper conductor.

Last comes a pair of plastic sheaths, which protects both the phosphor material (moisture can ruin some phosphors) and the user from electric shocks.

EL wire needs a high voltage -- around 100 volts -- to glow brightly. Lower voltages result only in a dull glow. Some EL wires can produce a range of light wavelengths depending on the frequency of applied power. Elwire.com offers an "aqua" EL wire with a color that varies from deep green to deep blue as the user alters the power frequency from 60 hertz (Hz) to 6 Hz. Also, because EL wire needs an AC power system, any outfit that has EL wire will need a battery pack and an inverter -- a device that converts direct current (DC) power to AC power. To learn more about AC and DC power, read our article on How Electricity Works.

Because the core of EL wire is copper, it's flexible but holds its shape. You can bend EL wire into all sorts of designs. When it's turned off, EL wire looks like a colorful plastic tube, but when the power comes on, EL wire looks like thin strands of neon lights. An outfit with EL wire could have several different strands emitting different colors, and might even include a sequencer -- a special circuit board -- connected to the power source that manages each strand's power supply. By alternating power to various strands, the wire can appear to be animated as different strands flash on and off.

Clothes with EL wire require careful maintenance and cleaning procedures. If the wire is permanently affixed to the clothing, the wearer will need to carefully wash it by hand and let it dry on a flat surface, or rely on spot cleaning. Throwing electroluminescent clothes into the washing machine is a good way to ruin a special outfit, and could even damage other clothes or the washing machine itself if the plastic tubing around the copper core tears.

Electroluminescent clothes are bright and vibrant, and with the right equipment they can display lights in patterns and sequences, but they're still fairly static -- you're limited by the shapes into which you've bent the EL wire.

In the next section, we'll learn about LED fabric displays and how they give you more options to express yourself through clothing.

Phosphors

Electroluminescent substances are a kind of phosphor. Phosphors are materials that emit light after absorbing some form of radiation or as a result of a chemical reaction. Electroluminescent phosphors emit light after absorbing electricity.

Fabric Displays Using LEDs

Koninklijke Philips Electronics N.V. A model wears a LumaLive shirt designed by Philips.

Light emitting diodes (LEDs) are tiny light bulbs designed to fit into electrical circuits. Unlike incandescent bulbs, LEDs don't use a filament to generate light. Instead, light is a byproduct of electron motion within semiconductor material. Electrons move from high energy states to lower ones, releasing photons in the process. LEDs take advantage of this, harnessing and focusing the photons into tiny light bulbs. The gap between the higher and lower states of energy determines the frequency of the photon, which we observe as a specific color of light.

Several companies sell clothes that use LEDs to create special patterns or messages. Most of these companies will alter regular clothing to include LEDs. For instance, if you want to turn your normal jacket into an advertisement for HowStuffWorks, you'd send the jacket and a description of what you wanted to the alteration company. A company employee would cut small holes in the jacket and fit an LED into each hole. Once assembled, the lights spell out your message. On the inside of the jacket, each LED attaches to a circuit board. Most companies cover the circuitry with a thin fabric lining. The employee then attaches a power source, usually a small battery pack that can fit into a jacket, shirt or pants pocket.

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Other companies cover the LEDs with a thin fabric so that the plastic bulbs aren't visible. When turned on, the light shines through the thin cloth. Like electroluminescent clothing, clothes using LED technology must be carefully maintained and washed. Otherwise, the delicate circuitry could become damaged.

The circuitry controlling an LED display can be as simple as a power switch, meaning all the LEDs are either turned on or off, or it can include microprocessors, which let the wearer customize how the LEDs light on and off. This means that if a shirt has a block of RGB LED lights (LEDs that can emit any color of light), the wearer can create a program telling each LED when to turn on and off as well as what color it should be. By alternating colors and turning on and off, an LED fabric display can create simple images or messages. Each LED acts as a pixel, but because LEDs are much larger than television pixels, the resolution on an LED display won't be very sharp. Because of the low resolution, clothes with LEDs are best for simple messages or designs.

Using LED displays, you can have a preprogrammed light show on your clothing. But what if you want an even more impressive display? In that case, you'll need to look at technology that can display full moving pictures like television signals.

In the next section, we'll learn more about one of these technologies -- PLEDs.

Fabric Displays Using PLEDs

PLED stands for polymer light emitting diode, which is a technology used in backlighting, illumination and electronic displays. Unlike LEDs, which are small bulbs, a PLED display is a thin, flexible film made of polymers and capable of emitting the full color spectrum of light.

A PLED is constructed of several layers:

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An engineer begins with a glass or plastic substrate -- for PLED fabric displays, plastic tends to be a better choice because it's less fragile but more flexible than glass.

Next comes a transparent electrode coating, which an engineer applies to one side of the substrate.

Then the engineer coats the same side of the substrate with the light emitting polymer film.

The last layer is an evaporated metal electrode, which the engineer applies to the other side of the polymer film [source: Cambridge Display Technology].

When the engineer applies an electric field between the two electrodes, the polymer emits light, much like an LED. Because the polymers in PLED are made of organic molecules, they are also known as OLEDs -- organic light emitting diodes. To learn more about how these diodes can emit light, read our article on How OLEDs Work.

Using a PLED screen, it would be possible to create a fabric television. PLED displays are very thin and relatively light compared to other display technologies. Of course, the screen is just one important element in the overall fabric display -- you would also need a power source, such as a lithium-ion battery, and a signal source. The signal source could be a small computer containing preloaded video clips or even a WiFi-enabled device that could stream audio and video directly to your clothes.

Clothes using PLED displays aren't currently available, though several Web pages list fabric displays as a likely PLED application in the near future.

In the next section, we'll look at how an invention called T-Shirt TV works and the impact it's made on advertising.

What's a Polymer?

Polymers are chains of repeated molecular structures. The shape of the molecular structure determines the polymer's properties. For example, graphite and diamonds are both inorganic carbon polymers -- they have different properties because of the way the carbon atoms bind together to form molecules. The molecular structure of the polymers in PLEDs is what gives them the ability to emit light after electrical stimulation.

T-Shirt Television

In 2004, Brand Marketers introduced Adver-Wear, shirts with built-in 11-inch television screens and a four-speaker sound system. Adam Hollander designed and produced the first Adver-Wear shirts -- also known as T-Shirt TV -- because he felt that static advertisements don't reach younger consumers. In interviews, Hollander said that young people had become so used to television that marketers needed to find new ways to incorporate video and animation in advertising strategies or risk losing customers.

The shirts weigh about six and a half pounds. Because they use flat panel television screens, the shirts are a little bulky. Hollander created the shirts specifically for advertising, with no intention of offering them to the public, so comfort and practicality weren't of much concern in the design process. The components are also too expensive to sell T-Shirt TV clothing to the consumer market.

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In addition to the screen and speaker system, the shirts need a portable power source -- usually in the form of a lithium-ion battery. It also needs a video source: a custom-built computer that can store and play digital media efficiently. Brand Marketers can incorporate the system into most types of clothes as well as include interactive features like a handheld touch-screen if clients request it. Currently, the systems can play any length of audio or video files separately or in a loop. Future versions of the shirt will include Bluetooth and WiFi capability, adding more interactive features to the clothing.

The marketing firm Adwalker offers a similar product: A portable, wearable computer system. A padded harness acts as the frame for the system, which includes a portable PC, computer monitor, a handheld touch screen and a printer. Clients can send Adwalker videos, software, logos and other computer files and Adwalker incorporates them into eye-catching presentations. An Adwalker employee wears the harness and interacts with the general public. Using this system, the Adwalker employee can:

Display graphics like company logos or screenshots of Web pages on the computer monitor

Play video and audio

Run interactive computer software, including games, which members of the public can access using the handheld touch-screen

Print tickets, coupons or brochures for customers

Capture customer data using spreadsheet or database software

Interact with the public and answer questions about the advertised product

The system is bulkier than Adver-Wear, but it's even more interactive and has more functions than T-Shirt TV.

As advertising companies continue to search for new ways to grab our attention, we'll likely see more applications of fabric displays. We may even see applications where entire outfits act like a television screen, with images wrapping around from front to back.

To learn more about fabric displays and related topics, follow the links on the next page.

Coming to a T-shirt Near You

Adver-Wear made a big splash during the promotional campaign for the Will Smith film "I-Robot." Models in several different cities wore Adver-Wear shirts with screens playing a looped preview for the film. The marketing campaign caught national news attention.